Field of the Invention
In any industry where the use of coal requires handling of large quantities, a recurring problem is the presence of coal dust. The latter occurs as a result of the ordinary handling of coal since dust is continually generated so long as the coal is moved about or transported.
For example, when large quantities of coal are transported by rail, the coal is deposited into a hopper-containing car, referred to hereinafter as a hopper car. The latter includes a series of hopper-like containers having open tops and constricted discharge openings at the bottom. For discharging this dust-containing cargo, the hopper car is first positioned over a receptacle such as a storage bin, tank or the like. Thereafter the bottom discharge ports are opened, permitting the coal to fall by gravity into the containing receptacle.
To facilitate removal of the coal, which under some circumstances can become jammed in the hopper, the hopper car is submitted to a shaking or vibratory action. This normally loosens the coal mass such that it is free to flow through the discharge openings.
It can be appreciated that the unloading of such a cargo can result in the accumulation of a considerable amount of coal dust. Some of the latter will be carried along with the flowing coal and pass into the storage facility. On the other hand, it has been found that the downwardly moving coal mass when replaced with air, will force the coal dust upwardly through the top opening of the hopper car thereby driving the dust into the atmosphere.
It has been determine through necessity and practice that to simplify the unloading of coal from a hopper car, the use of a car shaker or vibrator can be helpful. Such an apparatus is one that is motor driven and removably fixed to a hopper car at the time of unloading. The shaker mechanism normally includes a member which extends across the top opening of the hopper car. Thereafter, as the shaker vibrates, the entire hopper car will be comparably shaken, thus promoting the loosening and downward flow of the coal cargo.
To minimize the discharge of coal dust into the atmosphere, it has been found that applying a liquid such as water into the coal discharge area, can minimize or dampen the discharge of dust.
Toward overcoming or minimizing this undesirable factor of coal dust polluting an unloading area, the present apparatus is addressed to a dust confinement means which cooperates with a hopper car shaker in a manner to accumulate and collect the dust which ordinarily remains after the coal is discharged. The dust confinement means is comprised in brief of a flexible wall member which is internally supported to define a chamber or partial enclosure across the top of the hopper car shaker. The dust confining apparatus is sealably fixed to the top opening of the car shaker so that as a load is discharged from the hopper car, the coal dust will rise up into the flexible walled compartment.
Concurrently, the dust confinement means includes spray nozzles directed into the collecting or intermediate compartment whereby a file mist or water spray can be discharged therein to contact the dust particles.
The dust accumulating compartment is communicated with a reduced pressure source such as a bag house, which will maintain a reduced pressure in the compartment once it has been sealably fixed, thereby aspirating the major part of the dust and very light liquid droplets into the bag house.
It is therefore an object of the invention to provide means to minimize the loss of coal dust during a cargo discharging operation from a hopper car. A further object is to confine and collect coal dust which results from the discharge of a cargo of coal from a hopper car into a storage means. A still further object is to create a safe and clean environment for workers in an area where coal is ordinarily unloaded from hopper cars and into a storage area.